1. Field of the Invention
The present invention relates to an applied technology of a large capacity double layer capacitor.
2. Description of Related Art
The inventors of this application have developed electric double layer capacitors capable of storing a large amount of electric energy. The electric double layer capacitor realizes a large electrostatic capacitance by forming an electric double layer using electrodes formed of solid activated carbon to substantially increase an equivalent area of the electrodes. A series resistance component of the electric double layer capacitor can be substantially reduced by suitably selecting electrolyte. A structure, an operational principle and a manufacturing method thereof are disclosed in, for example, Japanese Patent Publication No. Hei 7-91449, Japanese Patent Application Laid open No. Hei 7-201677, Saito et al. "Development of High Double Layer Capacitors", NEC Technical Report Vol. 47, No. 10 (October, 1994), pp 91.about.96 and Saito et al. "High-Power Electric Double Layer Capacitor Using Block-Form Activated Carbon Electrode", Monthly New Ceramics, Vol. 9, No. 12 (December, 1996), pp 21-25. The inventors of this application have fabricated an electric double layer capacitor of 15V, 470F having an equivalent series resistance of 4 m .OMEGA. and a maximum discharge current of 600 A and reported already. This electric double layer capacitor can store an electric power of about 15 Wh when charged to a maximum terminal voltage.